US1674390A - Method of treating hydrocarbons - Google Patents

Description

Patented June 19, 1928.

UNITED STATES 1,674,390 PATENT OFFICE.

LUIS DE ELOREZ, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO THE TEXAS COMPANY, 01' NEW YORK, N. Y., A CORPORATION OF DELAWARE.

METHOD OF TREATING HYDROCARBONS.

Original application filed July 8, 1919, serial'lio. 309,500. Divided and this application filed August 4,

1922. Serial No. 579,602.

The present invention relates to improve ments in methods of cracking oils to produce low boilin hydrocarbons from similar materials of re atively high boiling points. One object of the invention is to produce, in commercial quantities, a distillate of suitable characteristics to be used as fuel in internal combustion engines, in such a manner as to reduce the loss of valuable products commonly resulting in so-ealled cracking operations as heretofore practiced.

The present application is a divisional of my pending application, Serial Number 309,500, filed July 8th, 1919.

Various methods of cracking or decomposing hydrocarbons by subjecting them to relatively high pressures and temperature, as heretofore generaly practiced, have frequently involved material losses in the form of undesirable products produced in too great proportion during the recovery of valuable products. These undesirable products include gas, residue, or high boiling point material and coke. It is known in connection with so-called cracking operations, that a certain proportion of material will go to form a gaseous product which retains its identity as a gas at normal temperature and pressure, while the balance will produce liquid products of low boiling'and high boiling properties. The proportion in which these products are formed is a relatively constant one, that is to say, with a given method of treatment of a given raw material and. assuming no defects in the apparatus, gas and liquid products will be formed in virtually uniform proportion. It has been observed that, if during the operation of the cracking process, a portion of the gas resulting from the cracking of a given amount of raw material be withdrawn from the system, a new formation or readjustment of the relative amounts of gas and liquids will take place and it will be found that an additional amount of gaseous products will be formed, thus increasin the gaseous prodnet at the expense of the iquid product. To avoid this loss of liquid product where it is desired. to withdraw gas for certain useful purposes, I propose to inject a portion of the gas normally formed by operation of the .piocess, or otherwise provided, into the system along with the oil which is under treatment, so that a balance between the, gaseous compounds and other products will be established to such an extent as to minimize the formation of new gas. It is contemplated that the formation of less gas from each increment of material treated will tend to incrcase the proportion of desired liquid products.

One embodiment of suitable apparatus for practicing my improved method is illustrated in part diagrammatically in the drawings accompanying the present specification, and in which Figure 1 is a schematic view generally in elevation but with portions broken away and portions in vertical section,

Figure- 2, a horizontal section on the line 2-2 of Figure 1, and

Figure 3, a detail view partly in vertical section showing connection between the oil vapor conduit and the gas conduit,

Referring to said drawings, the liquid hydrocarbon to be treated may be drawn from a suitable container, such as a running tank 1, by means of a. pump 2 arranged to force the oil into an expansion chamber or riser 3. From this expansion chamber, and by reason of the pump pressure, the hydrocarbon passes through a filter 4 constructed in such a manner as to remove from said hydrocarbon all sediment and solid materials. The hydrocarbon thus purified flows through a meter 5 either at the pressure substantially as produced by pump 2, or at a reduced pressure efi'ccted b means of a regulating valve 6 interposed etween said meter and the filter 4. In case it is desired to reduce the pressure after passage of the hydrocarbon through the meter, a regulating valve 7 may be provided. After passing through the meter, the hydrocarbon may be heated to a predetermined temperature by any suitable means, here shown as a coil 8 enclosed in a steam chest 9.

The apparatus may also include a suitable furnace for heating the hydrocarbon from atmospheric temperature to a suitable oil cracking temperature, such as approximately 610 centigrade, a preferred form of said furnace being indicated diagrammatically in the drawings and comprising substantially a combustion chamber 11" and a heating chamber 11 communicating therewith and having a baflle ll'interposed in the path of the products of combustion'whichmay be rmittedto escape through a' flue 12 and t ence to the atmos here t rough a chimney 13, if desired. T e h drocarbon coming from the steam heated coi 8 through a feed pipe 10 is carried through the heating chamber of the furnace through a suitable conduit 44 comprising a series of bends of ipe depending into the heating chamber rom a suitable supporting element or top plate 14. The bends of pipe comprising the conduit supported by the top plate 14, are connected in series and are of such dimensions that the hydrocarbon flows successively from pi es .of relatively largediameter to pipes o relatively small diameter. As

shown in Figure 1, the hydrocarbon carrying feed pipelO discharges the h drocarbon into conduit 44 at a relatively coo portion of the heating chamber and the temperature of the hydrocarbon isw radually raised as it passes through convo utions of the conduit depending in increasingly hotterportions of the heating chamber. 2A suitable arrangement of pipes constituting the conduit for conveyin the hydrocarbon through the heating 0 amber may include a plurality of two inch pi s receiving hydrocarbon directly from t e feed ipe 10. From the two inch pipes, the hy rocarbon may be led through a plurality ,of one and one-half inch pipes and thence into a plurality of one inch pipes, said one inch pipes being arranged in that portion of the heating chamber in which the maximum or redetermined cracking temperature is avai able.

It is contem lated that the h 'drocarbon will be entire y vaporized, un er normal conditions of operation, in a portion of the conduit located in a cooler portion of the heating chamber than that in which the cracking takes place. The vapor thus formed will then pass into pipes located in a relativel hotter ortion of the chamber where crac ing will e effected, the resulting product being then carried to an ex ansion chamber in which it is intended t at the deposition of carbon and other residual products shall take place, such as materials aving boiling points ranging from 300 to 400 centigra'de, if desired. The expansion chamber 15 may include a receptacle 16 having a baflle' 17 arranged opposite the opening of expansion chamber 15, said receptacle and baflie being adapted to efiect a further deposition of carbon which may be readily removed from said receptacle through a door 18 hinged to the bottom'of said receptacle. A condensing chamber 19 encloses a condenser coil 20 carrying the vaporized and cracked hydrocarbon, said coil being arranged to discharge the prodnets. of condensation into a receptacle or tank 21 from which the liquid deposit may be withdrawn through a suitable pi e 22 lo a storage tank 23. said pipe 22 eing provided with a valve 24. A door 25 ay be secured to the bottom of tank21 for the purpose of removing sedimentary deposits too eavyto flow through the pipe 22. The

product thus normally drawn oif through the pipe '22 will include thev distillates of the pipes, and after cracking has occurred the vapors will pass successively into the expansion chambers 15 and 16, thus progressively decreasing their velocity and. allowingthe deposition of the residual less volatile reaction products.

Under normal the tank 21 will also contain a hydrocarbon gas resulting, from the condensation of the vaporized and cracked hydrocarbon. A portion of this gas may be withdrawn from tank 21 by means of a conduit 26 controlled;

by a valve 27 and conducted through said conduit to the combustion chamber of the heating unit where the gas may be utilized to produce the heat required in the operation of va orization and cracking the hydrocarbon in conduit 44.

In order to maintain a redetermined cracking temperature in sai' conduit and in the heating chamber of the heating unit suitable temperature controlling means may be provided including a pyrometer 28 of any suitable construction preferably arranged in a portion of the con uit which carries the cracked hydrocarbon. This pyrometer may be operatively connected with an indicator dial 29 arranged in such position that the operator ma readily perceive any deviation from t e predetermined temperature. and control said temperature by increasing or diminishing the supply of fuel in the combustion chamber. or this purpose, a hand operated valve 30 may be provided. Obviously, the adjustment of fuel supply may be automatic by suitable controlling mechanism interposed between a fuel supply controlling valve and the pyrometer 28.

Another portion of the gas formed in tank 21 may be drawn therefrom through a ipe 81 an into a compressor 32 from which it is forced through a condenser 33 and into a reservoir 34. Any liquid or distillate deposited in this reservoir by reason of the further cooling of the gas may be withdrawn therefrom through a pipe 35 controlled by a valve 36 into the storage tank 23.

Where it is desired to utilize the gas pumped into tank 34 as described by introducing it into the hydrocarbon at any de sired point in the cracking operation, a feed conditions of operation, Y

assing from the cooler or vaporizing.

lea

admitted to these various parts may be in part controlled through manipulation of said valves. 7

Where it is desired to heat the gas drawn from tank 34, before introducing it into the portions hereinabove referred to, the gas may be deflected into a pipe 41 through a valve 42, under which conditions the valves 38, 39 and 40 may be either partiallyor entirely closed, as circumstances require. When valve 42 is open, gas may be fed through pipe 41 into a coil 43 located in the heating chamber of the heating unit and may be admitted into the expansion chamber 15 through a valve 46, or into feed pipe 10 through valve 48. I prefer, however, to introduce the gas through. valve 45 into the conduit 44 where the hydrocarbon is vaporized but before it is cracked.

In operation, it has been found that a suitable primary operating pressure on the liquid hydrocarbon is approximately 250 pounds, said pressure being developed in pump 2. stepped down to provide a feed pressure of 125 pounds either by means of the regulating valve 6 or the regulating valve 7 ar-- ranged respectively at either side of the meter 5, it being desirable to regulate the flow of hydrocarbon so that it may be constant. The initial feed pressure of 125 pounds is gradually reduced as theheating and cracking operation proceeds until thehydrocarbon reaches the distillate receiving tank 21 in which a pressure of approximately 15 pounds may be maintained. To force the gas from tank 34 into the circulating system at the. points hereinabove mentioned, or others, it will be found that a pressure of approximately 125 pounds or more will be required where the feed pressure is approx imately 125 pounds. v

This primary pressure may be In practicing the method hereinabove outlined in connection with the apparatus described, it will be understood that one of the objects of my invention is accomplished by introducing into the vaporized or vaporizing hydrocarbon a gas which has been produced in the process thus providing such an excess of gas in the cracked and vaporized hydrocarbon that a relatively smaller proportion of gas formation will be found to have taken place under condensation of said vaporized and cracked hydrocarbon than is ordinarily found Where the excess of gas is not so introduced. Thus, by restricting the amount of gas product, I proportionately increase the amount of the desired liquid product thereby effecting a material economy in the operation of a plant of the character described.

I claim as my invention:

1. The process of converting liquid hydrocarbons which comprises continuously vaporizing oil in a vaporizing zone and heating the vapors to a cracking temperature in a cracking zone under pressure, progressively increasing the velocity of the hydrocarbons as they flow through said vaporizing and cracking zones, discharging the vapors from the cracking zone and expanding them in such manner as to progressively decrease their velocity, and condensing the vapors remaining after expansion.

2. In the process of converting hydrocarbon oils into relatively lower boiling hydrocarbon oils, the steps which comprise continuously supplying oil under ressure to the vaporizing section of a, tubu ar heater, effecting substantially complete vaporization of the oil therein, passing the hot vapors into another section of said heater to effect cracking of the vapors therein, passing the cracked vapors ,into expansionchambers of successively increasing size, whereby the residual less volatile products are deposited, and thereafter condensing the remaining vapors.

In testimony whereof, I have signed my name to this specification this first day of August 1922.

LUIS on FLOREZ.

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